predicting tectonic geohazrds

Question 1

physical properties x3

Answer 1

large earthquakes preceded by smaller ones
p wave velocity may decrease then increase
coloured lights in the sky immediately before

Question 2

what may cause coloured lights in the sky before an earthquake?

Answer 2

changes in electrical properties of quartz and other minerals under stress

Question 3

stress x3

Answer 3

minute cracks in rock allow percolation of water + gases, increasing electrical conductivity+ lowering resistivity
area around focus may tilt
levels in wells decrease+ replenish before earthquake

Question 4

animal behaviour

Answer 4

animals show disturbed behaviour e.g. pigs squeal, dogs bark

Question 5

why may animals behave differently right before an earthquake? x3

Answer 5

may feel p wave arrival, low magnitude foreshocks of slight changes in earth’s magnetic field

Question 6

radon emission

Answer 6

radon accumulates in water wells so an increase= gas is percolating through new micro cracks

Question 7

seismic gap model

Answer 7

next big earthquake expected in gap between recently slipped sections, where there is more stored energy

Question 8

how are tsunamis an early warning system for earthquakes?

Answer 8

movement of crust= tsunami which = an earthquake

Question 9

what are tsunamis associated with?

Answer 9

high magnitude earthquakes

Question 10

tsunami hazard management x3

Answer 10

warning by siren, radio, loud speaker
signs showing evacuation to high ground
education that retreating sea=tsunami

Question 11

how can you save properties on the coast from tsunamis?x4

Answer 11

maintaining coral reefs in good condition
maintaining coastal trees and vegetation
prohibiting building along coast
designing buildings with no permanent accommodation on ground floor